WO2023108663A1 - 一种基于压电陶瓷传感器的超精密切削准静态力检测系统 - Google Patents

一种基于压电陶瓷传感器的超精密切削准静态力检测系统 Download PDF

Info

Publication number
WO2023108663A1
WO2023108663A1 PCT/CN2021/139402 CN2021139402W WO2023108663A1 WO 2023108663 A1 WO2023108663 A1 WO 2023108663A1 CN 2021139402 W CN2021139402 W CN 2021139402W WO 2023108663 A1 WO2023108663 A1 WO 2023108663A1
Authority
WO
WIPO (PCT)
Prior art keywords
force
piezoelectric ceramic
value
moment
time
Prior art date
Application number
PCT/CN2021/139402
Other languages
English (en)
French (fr)
Inventor
陈远流
陈甫文
林焕斌
李忠伟
居冰峰
Original Assignee
浙江大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 浙江大学 filed Critical 浙江大学
Priority to PCT/CN2021/139402 priority Critical patent/WO2023108663A1/zh
Publication of WO2023108663A1 publication Critical patent/WO2023108663A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices

Definitions

  • the invention relates to the technical field of ultra-precision cutting, in particular to a quasi-static force detection system for ultra-precision cutting based on piezoelectric ceramic sensors.
  • Ultra-precision cutting technology using ultra-precision lathes with nano-machine positioning accuracy and diamonds with sharp edges, high hardness, and good wear resistance as tools, the geometric surface is formed by accurately controlling the relative motion trajectory between the tool and the workpiece, and nano-scale Surface roughness and sub-micron shape accuracy Micro-nano-structured surfaces.
  • This technology is an important means of manufacturing optical components with micro-nano fine structure or high-precision morphology. It is widely used in the fields of aerospace, national defense and military industry, information communication, life science and material science. It is an important branch in the field of ultra-precision processing. .
  • micro-nano fine structure is formed in a large-scale distribution according to a certain geometric law in a large-scale range.
  • the market prospect of surfaces with specific functions requires effective online detection of ultra-long-term and high-dynamic processes of cross-scale processing.
  • the cutting force can reflect the effective information of the processing state. Therefore, the state of ultra-precision cutting processing is often detected online by detecting the change of cutting force in real time.
  • the traditional ultra-precision cutting force detection method is mainly realized by commercial dynamometers, but the existing commercial dynamometers have the problem of poor structural dexterity, and it is difficult to integrate them on ultra-precision cutting devices for high dynamic , Highly sensitive cutting force detection.
  • Piezoelectric ceramics can be used as force sensors based on the positive piezoelectric effect, and have the advantages of dexterous structure and high sensitivity. They are often integrated in ultra-precision cutting tools/workpieces to detect cutting forces during processing. However, piezoelectric ceramics have a serious charge leakage problem, and are often used to detect alternating dynamic force processes (the force alternating process will continuously charge piezoelectric ceramics to compensate for the problem of charge leakage), but it is difficult to detect static forces or quasi-static forces. force.
  • the cutting process is a dynamic and quasi-static process that can only be used to detect dynamic forces and cannot detect quasi-static force piezoelectric ceramic force sensors, so it is difficult to meet the complete ultra-precision cutting state detection requirements.
  • the purpose of the present invention is to provide a method based on charge leakage dynamic compensation to realize a quasi-static force detection system for ultra-precision cutting based on piezoelectric ceramic sensors.
  • a quasi-static force detection system for ultra-precision cutting based on piezoelectric ceramic sensors including
  • Piezoelectric ceramic force sensing unit which is set at the processing end of the ultra-precision cutting system and used to load single-point diamond tools
  • the piezoelectric ceramic force sensing unit is subjected to the force of the single-point diamond tool and generates a charge signal to an external post-processing module.
  • the post-processing module includes:
  • the pre-charge amplifier circuit is used to amplify the signal detected by the piezoelectric ceramic force sensing unit
  • a low-pass filter circuit is used to filter the output signal of the pre-charge amplifier circuit
  • the ADC module is used to convert the voltage signal passed by the low-pass filter circuit into a corresponding digital signal
  • DSP signal processor used for real-time processing of digital signals, and transmits the processed data to the computer
  • the computer based on the solution of the dynamic changing force f i at each moment, obtains the actual force F i acting on the piezoelectric ceramic force sensor at the i-th moment by accumulating the dynamic changing force at the previous i moment;
  • T is the time interval between time i and time i-1;
  • ⁇ is the time constant of charge leakage decay
  • U i is the actual voltage output of the pre-charge amplifier circuit at the current moment
  • U i-1 e -T/ ⁇ is the attenuation result of the voltage output U i-1 by the charge leakage effect at the previous moment;
  • c is the linear coefficient between the output voltage of the pre-charge amplifier circuit and the force value of the piezoelectric ceramic.
  • the post-processing module further includes: a charge leakage dynamic compensation module, which is based on the output voltage change value
  • and the voltage attenuation threshold u th2 u i-1 (1-e -T/ ⁇ ) within the cycle time T compensate the voltage output U i of the pre-charge amplifier circuit at the current moment.
  • a charge leakage dynamic compensation module which is based on the output voltage change value
  • and the voltage attenuation threshold u th2 u i-1 (1-e -T/ ⁇ ) within the cycle time T compensate the voltage output U i of the pre-charge amplifier circuit at the current moment.
  • a method for detecting quasi-static force in ultra-precision cutting based on a piezoelectric ceramic sensor comprising the following steps:
  • Step 1 detect the voltage signal on the piezoelectric ceramic force sensor in real time, and record the output value U i of the charge amplifier at this moment; when the cutting starts, the first detected output value U i of the charge amplifier is the actual output voltage of the charge amplifier at this moment U 1 , calculate the actual force of the piezoelectric ceramic force sensor for the first time
  • Step 2 use the observed voltage U i at the current moment and the voltage U i-1 at the previous moment to calculate the dynamic change voltage ⁇ U i due to the dynamic force, namely
  • T is the time interval between time i and time i-1;
  • ⁇ is the time constant of charge leakage decay
  • U i-1 e -T/ ⁇ is the attenuation result of the voltage output U i-1 by the charge leakage effect at the previous moment;
  • Step 3 calculate the dynamic force f i at the current moment
  • c is the linear coefficient of the output voltage of the charge amplifier and the force value of the piezoelectric ceramic
  • Step 4 Based on the solution of the dynamic changing force f i at each moment, the actual force F i acting on the piezoelectric ceramic force sensor at the i-th moment can be obtained by accumulating the dynamic changing force at the previous i moment, namely
  • the voltage signal on the piezoelectric ceramic force sensor is filtered, specifically as follows:
  • the bias current is compensated: the output voltage is pre-calibrated to deviate from the time-related slope value k 1 , and the voltage value U i at time i is dynamically compensated U i ,
  • the temperature is compensated: the slope value k 2 related to the output voltage change and the temperature change is calibrated in advance, and the voltage value U i at time i is dynamically compensated U i ,
  • ⁇ T i is the change value of the ambient temperature at time i relative to the ambient temperature at the initial time.
  • the present invention amplifies the weak charge signal generated by the piezoelectric ceramic force sensor integrated in the ultra-precision cutting device during the stress process through a pre-charge amplifier circuit, and then sequentially passes through low-pass filtering on the basis of the pre-amplification circuit, ADC data acquisition, and then real-time processing of the signal in the DSP signal processor, starting from the principle of piezoelectric ceramic charge leakage effect, based on the dynamic compensation of piezoelectric ceramic force sensor charge leakage, to realize based on piezoelectric ceramic force.
  • the quasi-static force detection function of the sensor; through the results of the quasi-static force compensation algorithm described in the present invention the piezoelectric ceramic force sensor can be found not only to have a sensitive change at the moment of force change, but also to maintain this change. Therefore, the measurement of the quasi-static force can be realized, that is, the magnitude of the actual force acting on the piezoelectric ceramic force sensor can be reflected at any moment.
  • the invention has a smart structure and good integration performance. Compared with the commercial dynamometer, the structure is fixed and not smart enough.
  • the method of the present invention is realized based on the ordinary piezoelectric ceramic force sensor.
  • the piezoelectric force sensor is small in size and smart in structure, which is convenient for integration in ultra-precision cutting
  • the tool end of the device acts as a tool holder, enabling the perception of ultra-low cutting forces close to where ultra-precision machining occurs.
  • the present invention has a wide range of measurable forces.
  • the method described in the present invention can not only realize the traditional dynamic force detection function based on piezoelectric force sensors, but also break through the limitation that it is difficult to detect static force and quasi-static force due to the problem of charge leakage. , on the basis of high integration, high stiffness, and high sensitivity piezoelectric ceramic force sensor, the coverage measurement of dynamic force, quasi-static force and static force is realized.
  • Figure 1 is a schematic diagram of the comparison between the actual output and the ideal output of the quasi-static force loading and unloading of the piezoelectric ceramic force sensor.
  • Fig. 2 is a functional block diagram of the present invention.
  • Fig. 3 is a schematic diagram of a quasi-static force measurement algorithm based on dynamic compensation of piezoelectric ceramic charge leakage.
  • Fig. 4 is a block diagram of a quasi-static force measurement algorithm based on charge leakage dynamic compensation.
  • Fig. 5 is a schematic diagram of the bias current influence of the quasi-static force algorithm.
  • Fig. 6 is a schematic diagram of the influence of temperature on the quasi-static force algorithm.
  • Fig. 7 Schematic diagram of the comparison between the quasi-static force sensing system for ultra-precision cutting based on piezoelectric ceramic sensors and the measurement results of commercial dynamometers.
  • Fig. 8 is a schematic circuit diagram of the present invention.
  • Fig. 9 is a PCB diagram of the technical solution of the present invention.
  • the ultra-precision cutting device based on the piezoelectric ceramic sensor of the present invention is based on the traditional single-point diamond ultra-precision cutting system (fast tool servo device, slow tool servo device, etc.) , by integrating the piezoelectric ceramic force sensing unit, it is used to monitor the cutting force of the ultra-precision cutting process at the tool end on-line, so as to achieve the purpose of on-line monitoring of the processing status.
  • a quasi-static force detection system for ultra-precision cutting based on piezoelectric ceramic sensors including
  • Piezoelectric ceramic force sensing unit 1 which is arranged at the processing end of ultra-precision cutting system 14, and is used to load single-point diamond tool 13; piezoelectric ceramic force sensing unit 1 is a piezoelectric ceramic force sensor integrated in the ultra-precision cutting device , the weak charge signal generated during the stress process;
  • the piezoelectric ceramic force sensing unit 1 is subjected to the force of the single-point diamond tool 13 and generates a charge signal to an external post-processing module, and the post-processing module includes:
  • the pre-charge amplifier circuit 5 is used to amplify the signal detected by the piezoelectric ceramic force sensing unit 1;
  • a low-pass filter circuit 6 is used to filter the output signal of the pre-charge amplifier circuit
  • the ADC module 7 is used to convert the voltage signal transmitted by the low-pass filter circuit 6 into a corresponding digital signal
  • DSP signal processor 9 is used for the real-time processing of digital signal, and the data after processing is sent to computer 8;
  • Computer can be common PC machine;
  • the computer 8 based on the solution of the dynamic changing force f i at each moment, obtains the actual force F i acting on the piezoelectric ceramic force sensor at the i-th moment by accumulating the dynamic changing force at the previous i moment;
  • T is the time interval between time i and time i-1;
  • ⁇ is the time constant of charge leakage decay
  • U i is the actual voltage output of the pre-charge amplifier circuit at the current moment
  • U i-1 e -T/ ⁇ is the attenuation result of the voltage output U i-1 by the charge leakage effect at the previous moment;
  • c is the linear coefficient between the output voltage of the pre-charge amplifier circuit and the force value of the piezoelectric ceramic, which can be calibrated in advance according to the actual pre-charge amplifier circuit used.
  • e is the natural constant e.
  • the time interval T depends on the computing power of the processor, which affects the frequency of real-time processing.
  • the processor time interval used in the present invention is about 1ms, that is, 1k Hz; theoretically, the stronger the computing power of the processor, the faster the time interval T The shorter the value, the higher the accuracy.
  • the post-processing module further includes: a charge leakage dynamic compensation module 10, which is based on the output voltage change value
  • and the voltage attenuation threshold u th2 u i-1 (1-e -T/ ⁇ ) within the cycle time T compensate the voltage output U i of the pre-charge amplifier circuit at the current moment.
  • a charge leakage dynamic compensation module 10 which is based on the output voltage change value
  • and the voltage attenuation threshold u th2 u i-1 (1-e -T/ ⁇ ) within the cycle time T compensate the voltage output U i of the pre-charge amplifier circuit at the current moment.
  • a method for detecting quasi-static force in ultra-precision cutting based on a piezoelectric ceramic sensor comprising the following steps:
  • Step 1 real-time detection of the voltage signal on the piezoelectric ceramic force sensor, and record the output value U i of the charge amplifier at this moment; the dynamic change force acting on the piezoelectric ceramic force sensor at any time is f i , then the dynamic force is for The contribution of the output of the charge amplifier at this moment is ⁇ U i ,
  • the output value Ui of the charge amplifier detected for the first time is the actual output voltage U1 of the charge amplifier at this moment, and the first dynamic change force f1 is the first actual force F1 of the piezoelectric ceramic force sensor.
  • Step 2 use the current moment charge amplifier output value U i and the previous moment charge amplifier output value U i-1 to calculate the dynamic change voltage ⁇ U i due to the dynamic force,
  • Step 3 calculate the dynamic changing force f i at the current moment
  • c is the linear coefficient of the output voltage of the charge amplifier and the force value of the piezoelectric ceramic
  • Step 4 Based on the solution of the dynamic changing force f i at each moment, the actual force F i acting on the piezoelectric ceramic force sensor at the i-th moment can be obtained by accumulating the dynamic changing force at the previous i moment, namely
  • the voltage signal on the piezoelectric ceramic force sensor is filtered, specifically as follows:
  • the bias current is an inherent phenomenon of the charge amplifier, and the existence of the bias current will cause the output voltage of the charge amplifier to deviate from a fixed slope without force input. , the effect of bias current on the output of the charge amplifier. Since the influence of the bias current on the output voltage of the charge amplifier is a linear bias, therefore, when the pre-calibrated output voltage deviates from the time-related slope value k 1 , the voltage value U i at time i is dynamically compensated U i , so as to realize the bias set current compensation.
  • the output voltage of the charge amplifier will deviate, thereby affecting the force value of the piezoelectric ceramic sensor calculated based on the output voltage of the charge amplifier.
  • the change of the output voltage of the charge amplifier becomes linearly negatively correlated with the temperature. Therefore, the slope value k 2 related to the output voltage change and temperature change is pre-calibrated, and the voltage value U i at time i is dynamically compensated U i , so as to realize temperature compensation;
  • ⁇ T i is the change value of the ambient temperature at time i relative to the ambient temperature at the initial time.
  • the piezoelectric ceramic force sensor can measure quasi-static force, and based on the bias current compensation module and temperature compensation module, the accuracy of quasi-static force detection can be realized.
  • the force loading method shown in Figure 7 is continuous loading and unloading of quasi-static force, where,
  • Figure 7(c) is the detection result of a commercial dynamometer. It can be found that the commercial dynamometer can also change and maintain the alignment static force, but the signal noise is relatively large, and the sensitivity of force detection is conveniently lower than that of the method described in the present invention. , unable to make effective and accurate perception of ultra-low cutting force.
  • each detection starts from zero.
  • the second detection on the basis of the current output voltage U 2 , subtract the residual charge U 1 e -T/ ⁇ after the leakage of U 1 because of the charge, that is, to obtain the second Detect the actual increased voltage ⁇ U 2 , then calculate the actual dynamic change force f 2 based on the actual increased voltage ⁇ U 2 , and then add the dynamic change force f 2 on the basis of F 1 to obtain the single-point diamond tool 13 in Actual force F 2 at the current moment, and so on.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)

Abstract

基于压电陶瓷传感器的超精密切削准静态力检测系统，包括压电陶瓷力感知单元（1），其受到单点金刚石刀具（13）的作用力并产生电荷信号至外部的后处理模块，后处理模块包括：前置电荷放大电路（5），低通滤波电路（6），ADC模块（7），DSP信号处理器（9）和计算机（8）；计算机（8），基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i；从压电陶瓷电荷泄露效应原理出发，基于对压电陶瓷力传感器电荷泄露的动态补偿，来实现基于压电陶瓷力传感器的准静态力检测功能。

Description

一种基于压电陶瓷传感器的超精密切削准静态力检测系统 技术领域
本发明涉及超精密切削技术领域，特指一种基于压电陶瓷传感器的超精密切削准静态力检测系统。
背景技术
超精密切削技术，采用纳米机定位精度的超精密车床和刃口锋利、硬度高、耐磨性好的金刚石作为刀具，通过精确控制刀具与工件之间相对运动轨迹来形成几何表面，获得纳米级表面粗糙度和亚微米级形状精度微纳结构表面。该技术是制造具有微纳米精细结构或高精度形貌的光学元件的重要手段，广泛应用在航空航天、国防军工、信息通讯、生命科学和材料科学等领域，是超精密加工领域中的重要分支。
针对工件的加工尺寸极端化、加工面形复杂化、加工结构精细化的发展趋势，以及跨尺度微纳结构表面(微纳米精细结构在大尺寸范围内根据一定几何规律大规模分布而形成的一类具有特定功能的表面)的市场前景，需要对跨尺度加工的超长时、高动态过程进行有效的在线检测。
切削力可以反映加工状态的有效信息，因此，常通过实时检测切削力的变化来在线检测超精密切削加工状态。
(1)传统的超精密切削力检测方法，主要是通过商用的测力计来实现的，而现有的商用测力计，存在结构灵巧性差问题，难以集成在超精密切削装置上进行高动态、高灵敏的切削力检测。
(2)压电陶瓷基于正压电效应可用作力传感器，且具有结构灵巧、灵敏度高等优点，常被集成在超精密切削刀具/工件端来检测加工过程中的切削力。然而压电陶瓷具有严重的电荷泄露问题，常用来检测交变的动态力过程(力交变过程会对压电陶瓷不断充电来弥补电荷泄露的问题)，而难以用来检测静态力或准静态力。而切削加工过程是一个集动态、准静态于一体的过程，只能用来检测动态力而无法检测准静态力的压电陶瓷力传感器，故难以满足完整的超精密切削状态检测需求。
如图1(a)所示，当对压电陶瓷力传感器加载准静态力时，压电陶瓷产生微 弱极化电荷，经电荷放大器放大，输出为脉冲电压，而由于电荷放大器中反馈电阻、反馈电容组成的回路的放电效果，导致该脉冲电压无法保持而会迅速衰减；反之，当卸载准静态力，压电陶瓷产生反向微弱极化电荷，经电荷放大器放大，输出为反向脉冲电压，而由于电荷放大器中反馈电阻、反馈电容组成的回路的放电效果，导致该脉冲电压无法保持而会迅速衰减。而理想的准静态力加载、卸载的输出结果如图1(b)所示，当加载准静态力时，输出电压会发生变化并保持，直到该准静态力卸载为止。因此，压电陶瓷力传感器囿于电荷泄露问题，难以对准静态力进行长时、稳定的检测。
发明内容
本发明的目的是提供一种基于电荷泄露动态补偿的方法，实现基于压电陶瓷传感器的超精密切削准静态力检测系统。
本发明的目的是这样实现的：
一种基于压电陶瓷传感器的超精密切削准静态力检测系统，包括
压电陶瓷力感知单元，其设置在超精密切削系统的加工端，并用于装载单点金刚石刀具；
所述压电陶瓷力感知单元受到所述单点金刚石刀具的作用力并产生电荷信号至外部的后处理模块，所述后处理模块包括：
前置电荷放大电路，用于放大压电陶瓷力感知单元检测到的信号；
低通滤波电路，用于对前置电荷放大电路的输出信号进行过滤；
ADC模块，用于将低通滤波电路传递过来的电压信号转换为相应的数字信号；
DSP信号处理器，用于数字信号的实时处理，并将处理后的数据传给计算机；
计算机，基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i；
Figure PCTCN2021139402-appb-000001
T为i时刻与i-1时刻的时间间隔；
τ为电荷泄露衰减的时间常数；
U i为当前时刻的前置电荷放大电路实际的电压输出；
U i-1e -T/τ为上一时刻电压输出U i-1经电荷泄露效应的衰减结果；
c为前置电荷放大电路的输出电压与压电陶瓷受力值的线性系数。
优选的，所述后处理模块还包括：电荷泄露动态补偿模块，其基于相邻两时刻输出电压变化值|u i-u i-1|与电路噪声阈值u th1，以及电压变化值|u i-u i-1|与周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)对当前时刻的前置电荷放大电路的电压输出U i进行补偿。
优选的，所述后处理模块还包括：偏置电流补偿模块，其基于预先标定的输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i＝U i-k 1·i。
优选的，所述后处理模块还包括：温度补偿模块，其基于预先标定的输出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i＝U i-k 2·ΔT i，其中ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
一种基于压电陶瓷传感器的超精密切削准静态力检测方法，包括以下步骤：
步骤一，实时检测压电陶瓷力传感器上的电压信号，并记录该时刻电荷放大器输出值U i；切削开始时，首次检测到的电荷放大器输出值U i为该时刻的电荷放大器实际的输出电压U 1，计算压电陶瓷力传感器首次的实际作用力
Figure PCTCN2021139402-appb-000002
步骤二，利用观测到的当前时刻的电压U i和上一时刻的电压U i-1，来计算由于动态力产生的动态变化电压ΔU i，即
ΔU i＝U i-U i-1e -T/τ；
T为i时刻与i-1时刻的时间间隔；
τ为电荷泄露衰减的时间常数；
U i-1e -T/τ为上一时刻电压输出U i-1经电荷泄露效应的衰减结果；
步骤三，计算当前时刻的动态力f i，
Figure PCTCN2021139402-appb-000003
c为电荷放大器输出电压与压电陶瓷受力值的线性系数；
步骤四，基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，即可得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i，即
Figure PCTCN2021139402-appb-000004
优选的，所述步骤一中，对压电陶瓷力传感器上的电压信号进行过滤，具体如下：
记录相邻两时刻输出电压变化值|u i-u i-1|，电路噪声阈值u th1和周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)；
在相邻两时刻输出电压变化值|u i-u i-1|大于电路噪声阈值u th1的时候，将该时刻的输出电压u i作为计算值U i代入到步骤三中；
在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且电压变化值大于衰减阈值u th2的时候，将该时刻的输出电压u i作为计算值U i代入到步骤三中；
在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且电压变化值小于或等于衰减阈值u th2的时候，将前一时刻电压u i-1衰减后的结果u i-1e -T/τ作为当前时刻计算值U i代入到步骤三中。
优选的，所述步骤一中，对偏置电流进行补偿：预先标定输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i，
U i＝U i-k 1·i。
优选的，所述步骤一中，对温度进行补偿：预先标定输出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i，
U i＝U i-k 2·ΔT i，
ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
本发明相比现有技术突出且有益的技术效果是：
本发明对于集成在超精密切削装置中的压电陶瓷力传感器在受力过程当中产生的微弱电荷信号，通过前置电荷放大电路对其进行放大，在前置放大基础上，依次经由低通滤波电路、ADC数据采集，进而在DSP信号处理器中对信号进行实时的处理，从压电陶瓷电荷泄露效应原理出发，基于对压电陶瓷力传感器电荷泄露的动态补偿，来实现基于压电陶瓷力传感器的准静态力检测功能；压电陶瓷力传感器经过本发明所述准静态力补偿算法的结果，可以发现不仅可以在受力变化瞬间有灵敏的变化，且可以维持这种变化保持不变，从而实现对准静态力的测量，即可以在任一时刻反映作用在压电陶瓷力传感器上的实际力的大小。
本发明的结构灵巧，集成性能好。相比于商用的测力计，结构固定、不够灵 巧，本发明所述方法是基于普通的压电陶瓷力传感器实现的，压电式力传感器体积小，结构灵巧，方便集成在超精密切削加工装置的刀具端作为刀具架，在靠近发生超精密切削加工的位置实现超低切削力的感知。
本发明的可测量力类型广，本发明所述方法，不仅可以实现传统的基于压电式力传感器动态力检测功能，还突破了囿于电荷泄露问题导致难以检测静态力、准静态力的局限，实现了在高集成度、高刚度、高灵敏的压电陶瓷力传感器基础上，实现动态力、准静态力、静态力的覆盖性测量。
附图说明
图1为压电陶瓷力传感器的准静态力加载、卸载的实际输出和理想输出的对比示意图。
图2为本发明的原理框图。
图3为基于压电陶瓷电荷泄露动态补偿的准静态力测量算法原理示意图。
图4为基于电荷泄露动态补偿的准静态力测量算法框图。
图5为准静态力算法的偏置电流影响示意图。
图6为准静态力算法的温度影响示意图。
图7基于压电陶瓷传感器的超精密切削准静态力感知系统与商用测力计测量结果对比示意图。
图8本发明的电路原理图。
图9本发明的技术方案的PCB图。
具体实施方式
下面结合附图对本发明的具体实施方式作进一步详细说明。
如图1-9所示，本发明所述的基于压电陶瓷传感器的超精密切削装置，是在传统的单点金刚石超精密切削系统(快速刀具伺服装置、慢速刀具伺服装置等)基础上，通过集成压电陶瓷力感知单元，用于实现在刀具端在线监测超精密切削过程的切削力，以达到在线监测加工状态的目的。
一种基于压电陶瓷传感器的超精密切削准静态力检测系统，包括
压电陶瓷力感知单元1，其设置在超精密切削系统14的加工端，并用于装载单点金刚石刀具13；压电陶瓷力感知单元1是集成在超精密切削装置中的压电陶瓷力传感器，其在受力过程当中产生的微弱电荷信号；
所述压电陶瓷力感知单元1受到所述单点金刚石刀具13的作用力并产生电荷信号至外部的后处理模块，所述后处理模块包括：
前置电荷放大电路5，用于放大压电陶瓷力感知单元1检测到的信号；
低通滤波电路6，用于对前置电荷放大电路的输出信号进行过滤；
ADC模块7，用于将低通滤波电路6传递过来的电压信号转换为相应的数字信号；
DSP信号处理器9，用于数字信号的实时处理，并将处理后的数据传给计算机8；计算机可以是普通的PC机；
计算机8，基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i；
Figure PCTCN2021139402-appb-000005
T为i时刻与i-1时刻的时间间隔；
τ为电荷泄露衰减的时间常数；
U i为当前时刻的前置电荷放大电路实际的电压输出；
U i-1e -T/τ为上一时刻电压输出U i-1经电荷泄露效应的衰减结果；
c为前置电荷放大电路的输出电压与压电陶瓷受力值的线性系数，可以根据实际采用的前置电荷放大电路进行提前标定。
e是自然常数e。
时间间隔T取决于处理器的计算能力，计算能力影响实时处理的频率，本发明使用的处理器时间间隔约为1ms，也就是1k Hz；理论上来说处理器的计算能力越强，时间间隔T越短，精度越高。
优选的，所述后处理模块还包括：电荷泄露动态补偿模块10，其基于相邻两时刻输出电压变化值|u i-u i-1|与电路噪声阈值u th1，以及电压变化值|u i-u i-1|与周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)对当前时刻的前置电荷放大电路的电压输出U i进行补偿。
优选的，所述后处理模块还包括：偏置电流补偿模块11，其基于预先标定的输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i＝U i-k 1·i。
优选的，所述后处理模块还包括：温度补偿模块12，其基于预先标定的输 出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i＝U i-k 2·ΔT i，其中ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
一种基于压电陶瓷传感器的超精密切削准静态力检测方法，包括以下步骤：
步骤一，实时检测压电陶瓷力传感器上的电压信号，并记录该时刻电荷放大器输出值U i；任一时刻作用在压电陶瓷力传感器上的动态变化力为f i，则该动态力对于该时刻电荷放大器输出的贡献为ΔU i，
ΔU i＝cf i         (1)；
切削开始时，首次检测到的电荷放大器输出值U i为该时刻的电荷放大器实际的输出电压U 1，首次的动态变化力f 1为压电陶瓷力传感器首次的实际作用力F 1，
Figure PCTCN2021139402-appb-000006
步骤二，利用当前时刻的电荷放大器输出值U i和上一时刻的电荷放大器输出值U i-1，来计算由于动态力产生的动态变化电压ΔU i，
ΔU i＝U i-U i-1e -T/τ         (2)；
步骤三，计算当前时刻的动态变化力f i，
Figure PCTCN2021139402-appb-000007
c为电荷放大器输出电压与压电陶瓷受力值的线性系数；
步骤四，基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，即可得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i，即
Figure PCTCN2021139402-appb-000008
优选的，所述步骤一中，如图4所示，对压电陶瓷力传感器上的电压信号进行过滤，具体如下：
记录相邻两时刻输出电压变化值|u i-u i-1|，电路噪声阈值u th1和周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)；
在相邻两时刻输出电压变化值|u i-u i-1|大于电路噪声阈值u th1的时候，说明此时电压变化是由外部动态力变化导致的，将该时刻的输出电压u i作为计算值U i代入到步骤三的公式(3)中；
在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且 电压变化值大于衰减阈值u th2的时候，说明电压变化由动态力变化引起，将该时刻的输出电压u i作为计算值U i代入到步骤三的公式(3)中；
在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且电压变化值小于或等于衰减阈值u th2的时候，将前一时刻电压u i-1衰减后的结果u i-1e -T/τ作为当前时刻计算值U i代入到步骤三的公式(3)中。
优选的，所述步骤一中，如图5所示，偏置电流是电荷放大器固有的现象，偏置电流的存在会导致在没有力输入的前提下，电荷放大器输出电压会存在固定斜率的偏离，偏置电流对电荷放大器输出的影响效果。由于偏置电流对电荷放大器输出电压的影响是线性偏置，因此，在预先标定输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i，从而实现偏置电流补偿。
U i＝U i-k 1·i。
优选的，所述步骤一中，如图6所示，环境温度的变化会导致电荷放大器输出电压出现偏离，从而影响基于电荷放大器输出电压计算得到的压电陶瓷传感器受力值。而温度变化对电荷放大器输出电压的影响，电荷放大器输出电压的变化与温度变成呈线性负相关。因此，在预先标定输出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i，从而实现温度补偿；
U i＝U i-k 2·ΔT i，
ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
综上，基于电荷泄露动态补偿实现压电陶瓷力传感器测量准静态力的功能，基于偏置电流补偿模块、温度补偿模块实现准静态力检测的精度。
为了进一步验证本发明所述方法的有效性，通过与商用测力计进行对比，对比结果如图7所示。图7所示的力加载方式是不断加载、卸载准静态力，其中，
图7(a)所示结果是压电陶瓷力传感器未经过算法补偿的结果，可以发现压电陶瓷力传感器可以在有力变化的瞬间输出电压有灵敏的变化，然而该变化无法保持，导致无法在任一时刻对压电陶瓷力传感器所受的实际力的大小进行有效判断；
图7(b)所示结果是压电陶瓷力传感器经过本发明所述准静态力补偿算法的结果，可以发现不仅可以在受力变化瞬间有灵敏的变化，且可以维持这种变化保持不变，从而实现对准静态力的测量，即可以在任一时刻反映作用在压电陶瓷力 传感器上的实际力的大小；
图7(c)是商用测力计的检测结果，可以发现商用测力计同样可以对准静态力作出变化与保持，然而信号噪声较大，在力检测的灵敏度方便比本发明所述方法低，无法对超低的切削力做出有效、准确度感知。
本系统的实际检测过程：每一次检测都是从零开始，开始切削时，首次检测到的电荷放大器输出值U i为该时刻的电荷放大器实际的输出电压U 1，通过公式获得首次的实际作用力F 1＝U 1/c；第二次检测的时候，在当前输出电压U 2的基础上，减去U 1因为电荷泄露之后残余的电荷U 1e -T/τ，即获得第二次检测实际增加的电压ΔU 2，再基于实际增加的电压ΔU 2，计算出实际的动态变化力f 2，再在F 1的基础上累加动态变化力f 2，即可获得单点金刚石刀具13在当前时刻的实际作用力F 2，依此类推。
上述实施例和说明书中描述的只是说明本发明的原理，在不脱离本发明精神和范围的前提下，本发明还会有各种变化和改进，这些变化和改进都落入要求保护的本发明范围内。本发明要求的保护范围由所附的权利要求书及其等效物界定。

Claims (8)

  1. 一种基于压电陶瓷传感器的超精密切削准静态力检测系统，包括
    压电陶瓷力感知单元(1)，其设置在超精密切削系统(14)的加工端，并用于装载单点金刚石刀具(13)；
    所述压电陶瓷力感知单元(1)受到所述单点金刚石刀具(13)的作用力并产生电荷信号至外部的后处理模块，其特征在于，所述后处理模块包括：
    前置电荷放大电路(5)，用于放大压电陶瓷力感知单元(1)检测到的信号；
    低通滤波电路(6)，用于对前置电荷放大电路的输出信号进行过滤；
    ADC模块(7)，用于将低通滤波电路(6)传递过来的电压信号转换为相应的数字信号；
    DSP信号处理器(9)，用于数据的实时处理，并将处理后的数据传给计算机(8)；
    计算机(8)，基于每一时刻动态变化力f i的求解，通过对前i时刻动态变化力的累加，得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i；
    Figure PCTCN2021139402-appb-100001
    T为i时刻与i-1时刻的时间间隔；
    τ为电荷泄露衰减的时间常数；
    U i为当前时刻的前置电荷放大电路实际的电压输出；
    U i-1e -T/τ为上一时刻电压输出U i-1经电荷泄露效应的衰减结果；
    c为前置电荷放大电路的输出电压与压电陶瓷受力值的线性系数。
  2. 根据权利要求1所述的一种基于压电陶瓷传感器的超精密切削准静态力检测系统，其特征在于，所述后处理模块还包括：电荷泄露动态补偿模块(10)，其基于相邻两时刻输出电压变化值|u i-u i-1|与电路噪声阈值u th1，以及电压变化值|u i-u i-1|与周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)对当前时刻的前置电荷放大电路的电压输出U i进行补偿。
  3. 根据权利要求1所述的一种基于压电陶瓷传感器的超精密切削准静态力检测系统，其特征在于，所述后处理模块还包括：偏置电流补偿模块(11)，其基于预先标定的输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i＝U i-k 1·i。
  4. 根据权利要求1所述的一种基于压电陶瓷传感器的超精密切削准静态力检测系统，其特征在于，所述后处理模块还包括：温度补偿模块(12)，其基于预先标定的输出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i＝U i-k 2·ΔT i，其中ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
  5. 一种基于压电陶瓷传感器的超精密切削准静态力检测方法，其特征在于，包括以下步骤：
    步骤一，实时检测压电陶瓷力传感器上的电压信号，并记录该时刻电荷放大器输出值U i；切削开始时，首次检测到的电荷放大器输出值U i为该时刻的电荷放大器实际的输出电压U 1，计算压电陶瓷力传感器首次的实际作用力
    Figure PCTCN2021139402-appb-100002
    c为电荷放大器输出电压与压电陶瓷受力值的线性系数；
    步骤二，利用当前时刻的电荷放大器输出值U i和上一时刻的电荷放大器输出值U i-1，来计算由于动态力产生的动态变化电压ΔU i，
    ΔU i＝U i-U i-1e -T/τ  ；
    T为i时刻与i-1时刻的时间间隔；
    τ为电荷泄露衰减的时间常数；
    U i-1e -T/τ为上一时刻电压输出U i-1经电荷泄露效应的衰减结果；
    步骤三，计算当前时刻的动态变化力f i，
    Figure PCTCN2021139402-appb-100003
    步骤四，基于每一时刻动态力f i的求解，通过对前i时刻动态变化力的累加，即可得到第i时刻作用在压电陶瓷力传感器上的实际作用力F i，即
    Figure PCTCN2021139402-appb-100004
  6. 根据权利要求5所述的一种基于压电陶瓷传感器的超精密切削准静态力检测方法，其特征在于，
    所述步骤一中，对压电陶瓷力传感器上的电压信号进行过滤，具体如下：
    记录相邻两时刻输出电压变化值|u i-u i-1|，电路噪声阈值u th1和周期时间T内电压衰减阈值u th2＝u i-1(1-e -T/τ)；
    在相邻两时刻输出电压变化值|u i-u i-1|大于电路噪声阈值u th1的时候，将 该时刻的输出电压u i作为计算值U i代入到步骤三中；
    在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且电压变化值大于衰减阈值u th2的时候，将该时刻的输出电压u i作为计算值U i代入到步骤三中；
    在相邻两时刻输出电压变化值|u i-u i-1|小于或等于电路噪声阈值u th1，而且电压变化值小于或等于衰减阈值u th2的时候，将前一时刻电压u i-1衰减后的结果u i-1e -T/τ作为当前时刻计算值U i代入到步骤三中。
  7. 根据权利要求5所述的一种基于压电陶瓷传感器的超精密切削准静态力检测方法，其特征在于，所述步骤一中，对偏置电流进行补偿：预先标定输出电压偏离与时间相关的斜率值k 1，对i时刻电压值U i进行动态的补偿U i，
    U i＝U i-k 1·i。
  8. [根据细则26改正 13.01.2022]
    根据权利要求5所述的一种基于压电陶瓷传感器的超精密切削准静态力检测方法，其特征在于，所述步骤一中，对温度进行补偿：预先标定输出电压变化与温度变化相关的斜率值k 2，对i时刻电压值U i进行动态的补偿U i，
    U i＝U i-k 2·ΔT i，
    ΔT i是i时刻环境温度相对于初始时刻环境温度的变化值。
PCT/CN2021/139402 2021-12-18 2021-12-18 一种基于压电陶瓷传感器的超精密切削准静态力检测系统 WO2023108663A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/139402 WO2023108663A1 (zh) 2021-12-18 2021-12-18 一种基于压电陶瓷传感器的超精密切削准静态力检测系统

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/139402 WO2023108663A1 (zh) 2021-12-18 2021-12-18 一种基于压电陶瓷传感器的超精密切削准静态力检测系统

Publications (1)

Publication Number Publication Date
WO2023108663A1 true WO2023108663A1 (zh) 2023-06-22

Family

ID=86775347

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/139402 WO2023108663A1 (zh) 2021-12-18 2021-12-18 一种基于压电陶瓷传感器的超精密切削准静态力检测系统

Country Status (1)

Country Link
WO (1) WO2023108663A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117889995A (zh) * 2024-03-15 2024-04-16 杭州微纳核芯电子科技有限公司 压电传感器控制方法、电路、压电感应系统和电子烟
CN117889995B (zh) * 2024-03-15 2024-06-04 杭州微纳核芯电子科技有限公司 压电传感器控制方法、电路、压电感应系统和电子烟

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7997144B1 (en) * 2007-05-11 2011-08-16 Purdue Research Foundation System and method of measuring quasi-static force with a piezoelectric sensor
CN103630273A (zh) * 2012-09-12 2014-03-12 贝辛电子科技（上海）有限公司 一种使用压电传感元件测量准静态力的装置
CN206002197U (zh) * 2016-07-28 2017-03-08 宁夏澍侍信息科技有限公司 一种物流运输振动监测系统
CN107300433A (zh) * 2017-06-19 2017-10-27 重庆大学 一种利用压电式力传感器测量静态力的方法
CN110253340A (zh) * 2019-06-26 2019-09-20 浙江大学 一种基于三轴快速刀具伺服机构的三维力检测系统

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7997144B1 (en) * 2007-05-11 2011-08-16 Purdue Research Foundation System and method of measuring quasi-static force with a piezoelectric sensor
CN103630273A (zh) * 2012-09-12 2014-03-12 贝辛电子科技（上海）有限公司 一种使用压电传感元件测量准静态力的装置
CN206002197U (zh) * 2016-07-28 2017-03-08 宁夏澍侍信息科技有限公司 一种物流运输振动监测系统
CN107300433A (zh) * 2017-06-19 2017-10-27 重庆大学 一种利用压电式力传感器测量静态力的方法
CN110253340A (zh) * 2019-06-26 2019-09-20 浙江大学 一种基于三轴快速刀具伺服机构的三维力检测系统

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117889995A (zh) * 2024-03-15 2024-04-16 杭州微纳核芯电子科技有限公司 压电传感器控制方法、电路、压电感应系统和电子烟
CN117889995B (zh) * 2024-03-15 2024-06-04 杭州微纳核芯电子科技有限公司 压电传感器控制方法、电路、压电感应系统和电子烟

Similar Documents

Publication Publication Date Title
CN108387338A (zh) 一种基于压电超声晶片的螺栓预紧力实时高精度检测方法及系统
CN110253340B (zh) 一种基于三轴快速刀具伺服机构的三维力检测系统
CN104977118B (zh) 一种差压传感方法及利用该方法的传感器探头
CN108956009A (zh) 一种压电式压力传感器校准方法及装置
CN114235229B (zh) 一种基于压电陶瓷传感器的超精密切削准静态力检测方法
CN104297500A (zh) 一种用于硬度测试的方法和装置
WO2023108663A1 (zh) 一种基于压电陶瓷传感器的超精密切削准静态力检测系统
Nguyen et al. PVDF sensor based characterization of chip segmentation in cutting of Ti-6Al-4V alloy
CN108955863B (zh) 一种基于电压倍增器的新型振动频率传感器系统
Liu et al. Milling force monitoring with thin-film sensors integrated into fixtures
GB580101A (en) Apparatus for investigating surface roughness
US3979670A (en) Apparatus for detecting and measuring peak-to-peak values in electrical signals
CN106247920B (zh) 一种基于弹性基底夹心叉指电容的表面应变检测器件
US10060806B2 (en) Multi-axis piezoelectric stress-sensing device, multi-axis piezoelectric stress-sensing device polarization method, and piezoelectric sensing detection system thereof
WO2005006397A3 (en) System and method for load sensing using piezoelectric effect
Tong et al. The research of screw thread parameter measurement based on position sensitive detector and laser
CN202533177U (zh) 新型改良红外测温仪的控制电路
CN103111642A (zh) 一种基于声表面波传感系统的智能刀具
CN207019625U (zh) 非接触长度测量装置
CN105973849B (zh) 光学材料损耗的测量装置和测量方法
Qin et al. Experimental study on an optical fiber acoustic emission sensor array
CN205449715U (zh) 钣金强度快速检测装置
CN110161838B (zh) 带压电力传感器静态漂移自动补偿的切削力主从控制系统
CN207675346U (zh) 一种具有三向微小高频切削力信号测量能力的传感器
CN101476896A (zh) 一种校零装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21967795

Country of ref document: EP

Kind code of ref document: A1